Last night, Lenovo had a big bash to celebrate the 20th anniversary of the ThinkPad. To mark the occasion, it showed off two new Ultrabooks and its first Windows 8 tablet. Dubbed the ThinkPad Tablet 2, it’s a sequel to the Android-based ThinkPad Lenovo released late last year, but really, it seems like an entirely new tablet all together. It’s the first fully-functional Windows 8 tablet I’ve seen. Though it’s still rough around the edges, it shows a lot of promise for the next version of Windows and for Lenovo’s chances in the tablet market.

Full Windows 8 with desktop apps

Here’s what’s awesome about the ThinkPad Tablet 2: It runs a full version of Windows 8. Unlike the first Surface tablet that will hit shelves, which will only run newer apps, the ThinkPad is essentially a full PC. You can install any app that you have on Windows Vista or Windows 7, as well as plug in any USB devices (it has a full USB port) to copy pictures or other things to your tablet. It won’t be as powerful as your laptop, but the ThinkPad shouldn’t have any compatibility issues or severe limitations out of the gate, like Android tablets do.

Windows 8 works much better on a tablet than it does on a laptop. It’s clear that the OS has been built for touch. Swiping and switching between apps and tasks is easy in the new design and everything is extremely responsive. Though the interface still has a Fischer-Price coloring scheme and look to it, everything works well.

On the negative side, while you do get that full Windows 7-style desktop environment, it isn’t pleasant to use. It works much better than touch versions of Windows 7 have worked, but every time I moved from the new Windows 8 Start Screen and apps into the old classic Windows desktop, it felt like a time warp. Several times, I watched the tablets flip out in desktop mode and start acting slow or unresponsive in that oh-so-familiar Windows way that we’ve known for 20 years. I watched a couple units have to be rebooted as well. Hopefully the final Windows 8 software won’t have these stability issues.

Surprisingly lean and powerful

One of the big things holding PCs from becoming good tablet computers for the last decade has been Intel. It’s processors have always required fans and haven’t been able to hold a charge for more than a few hours. Intel’s failure to produce battery and heat-efficient chips have lead to the entire phone and tablet industry favoring ARM processors. The iPad, the Galaxy S3, you name it and it’s running on an ARM chip. This year may mark a reversal of that trend. The ThinkPad Tablet 2 runs on a new Intel Atom processor. It’s as thin as any ARM device (9.8mm), doesn’t have a cooling fan, and supposedly gets 10-hour battery life. I’m skeptical on the battery life, but this is the most portable, thinnest Windows device I’ve ever used.

Lenovo has packed in a stylus as well. Though I don’t foresee using it much myself, there are many tasks that a stylus is just better for, including taking notes or trying to use classic desktop apps. It’s also nice that you can over the stylus much like you would a mouse and see a little dot to show where you’re pointing. This will be helpful when navigating complex Web pages with drop-down menus, and other intricate actions.

Looking good, Lenovo

Lenovo cannot control how Microsoft chooses to present Windows 8, but this tablet is already more useful than its Android predecessor and Lenovo’s design teams continue to bring out nice looking hardware. The demo units I tried were not 100 percent complete and glitched out a couple times, but they were thin, light, and very nice compared to almost any Android tablet. I still don’t know as I’d pick a Windows 8 tablet over an iPad, but if I needed backward compatibility or USB support, I suppose I’d have to — and many businesses do. There are a ton of unknowns right now, the biggest of which is the price. Assuming this is priced at $500 or less, Lenovo and Microsoft have a good shot of making a mark with the new OS.

(The video below shows off the ThinkPad 2. It cuts off at the end due to a problem with the demo unit. I was not able to get another video in good light. I apologize.)